Back to EveryPatent.com
United States Patent |
5,789,640
|
Jin
,   et al.
|
August 4, 1998
|
Aromatic hydrocarbons alkylation and liquid-solid circulating fluidized
bed for alkylation
Abstract
Disclosed is a process for continuous alkylation of aromatics or their
derivatives in the presence of a solid acid catalyst in a liquid-solid
circulating fluidized bed system, said system comprising a liquid-solid
cocurrent upflow reactor, a sedimentation washing tower for the used
catalyst, a liquid-solid cocurrent upflow regenerator, a sedimentation
washing tower for the regenerated catalyst, and two vortical liquid-solid
separators. By regeneration of the used catalyst, continuous alkylation
process is achieved in this system.
Inventors:
|
Jin; Yong (Beijing, CN);
Liang; Wugeng (Beijing, CN);
Wang; Zhanwen (Beijing, CN);
Yu; Zhiging (Beijing, CN);
Min; Enze (Beijing, CN);
He; Mingyuan (Beijing, CN);
Da; Zhijian (Beijing, CN)
|
Assignee:
|
China Petro-Chemical Corporation (Beijing, CN);
Tsinghua University (Beijing, CN);
Research Institute of Petroleum Processing Sinopec (Beijing, CN)
|
Appl. No.:
|
569234 |
Filed:
|
April 29, 1996 |
PCT Filed:
|
May 18, 1995
|
PCT NO:
|
PCT/CN95/00040
|
371 Date:
|
April 29, 1996
|
102(e) Date:
|
April 29, 1996
|
PCT PUB.NO.:
|
WO95/32167 |
PCT PUB. Date:
|
November 30, 1995 |
Foreign Application Priority Data
| May 24, 1994[CN] | 94105710.0 |
Current U.S. Class: |
585/467; 208/134; 422/144; 585/447; 585/921; 585/925 |
Intern'l Class: |
C07C 002/68; C10G 035/04; F27B 015/08 |
Field of Search: |
585/447,467,921,925,446
208/134
422/139,140,144,147
|
References Cited
U.S. Patent Documents
5012021 | Apr., 1991 | Vora | 585/315.
|
5489732 | Feb., 1996 | Zhang et al. | 585/467.
|
5565090 | Oct., 1996 | Gosling et al. | 208/134.
|
Other References
Vora et al., Tenside Surfactant Detergent 28(4), 287-294 (1991).
|
Primary Examiner: Caldarola; Glenn
Assistant Examiner: Bullock; In Suk
Attorney, Agent or Firm: Kane, Dalsimer, Sullivan, Kurucz, Levy, Eisele and Richard
Claims
What is claimed is:
1. A process for continuous alkylation of aromatics in the presence of a
solid acid catalyst, comprising
(a) contacting the reactants with a solid acid catalyst in a liquid-solid
concurrent upflow reactor (1);
(b) passing the liquid-solid mixture consisting of used solid acid catalyst
and the unreacted reactants and the products into a vortical liquid-solid
separator (2) to give separated used solid acid catalyst;
(c) passing said separated used solid acid catalyst through a sedimentation
washing tower (3) into a liquid-solid concurrent upflow regenerator (4);
(d) contacting said separated used solid acid catalyst in said regenerator
(4) with the regenerating reagent which is a reactant selected from the
group comprising aromatics;
(e) passing the liquid-solid mixture consisting of the regenerated catalyst
and the regenerating reagent into a vortical liquid-solid separator (5) to
give separated regenerated solid acid catalyst; and
(f) returning the separated regenerated solid acid catalyst to a
sedimentation washing tower (6), then into said reactor (1).
2. A process of claim 1, wherein said solid acid catalyst is solid
particles of a diameter of 0.05-0.8 mm, which are transported by the
reactants and the products or the regenerating reagents from the bottom to
the top of said reactor (1) or said regenerator (4) with the liquid flow
rate being 1-15 times the terminal settling velocity of the solid acid
catalyst, and the total flow rate of said solid acid catalyst, and the
reactants and products or the regenerating reagent being such that the
voidage of the fluidized bed is 0.68-0.95, and wherein the used or
regenerated solid acid catalyst together with the unreacted reactants and
the products or the regenerating reagent enters into said vortical
liquid-solid separator (2) or (5) in the tangent direction at a liquid
flow rate of 1-10 m/s.
3. A process of claim 1, wherein the contact between the solid acid
catalyst and the reactants is carried out at a temperature of
0.degree.-350.degree. C. and a pressure of 1-30 atm.
4. A process of claim 1, wherein the contact between the used solid acid
catalyst and the regenerating reagent is carried out at a temperature of
70.degree.-450.degree.C. and a pressure of 1-25 atm.
5. A process of claim 1, wherein the reactants enters into the reactor (1)
via the first inlet (7) and the second inlet (8).
6. A process of claim 1, wherein the regenerating reagent enters into the
regenerator (4) via the first inlet (11) and the second inlet (12).
7. A process of claim 1, wherein the separated used solid acid catalyst is
contacted with the washing reagent in the sedimentation washing tower (3)
with the washing reagent moving upward in the tower (3) at a velocity
0.5-5 times the terminal settling velocity of the used solid acid
catalyst.
8. A process of claim 7, wherein the washing reagent is the same as the
regenerating reagent, which is a reactant selected from the group
comprising aromatics.
9. A process of claim 1, wherein the regenerated solid acid catalyst is
contacted with the washing reagent in the sedimentation washing tower (6)
with the washing reagent moving upward in the sedimentation washing tower
(6) at a velocity 0.5-5 times the terminal settling velocity of the solid
acid catalyst.
10. A process of claim 9, wherein the washing reagent is the same as the
regenerating reagent, which is a reactant selected from the group
comprising aromatics and their derivatives.
11. A liquid-solid circulating fluidized bed system for the process of
claim 1, which comprises a liquid-solid concurrent upflow reactor (1), a
sedimentation washing tower (3) for the used catalyst, a liquid-solid
concurrent upflow regenerator (4), a sedimentation washing tower (6) for
the regenerated catalyst, and two vortical liquid-solid separator (2) and
(5), wherein the top of said reactor (1), which has two inlets (7) and (8)
for reactants, connects with said vortical liquid-solid separator (2),
which in turn connects with the top of said sedimentation washing tower
(3), and the bottom of said reactor (1) connects with the bottom of
sedimentation washing tower (6), and wherein the top of said regenerator
(4), which has two inlets (11) and (12) for regenerating reagent and is
set up parallel to said reactor (1), connects with said vortical
liquid-solid separator (5), which in turn connects with the top of said
sedimentation washing tower (6), and the bottom of said regenerator (4)
connects with the bottom of said sedimentation washing tower (3).
12. A system of claim 11, wherein connecting the two inlets of said reactor
(1) and said regenerator (4) is a combined distributor (9) respectively,
which is composed of a multi-tube distributor (14) with an opening ratio
of 2-15% and a porous plate distributor (15) with an opening ratio of
0.5-5%.
13. A system of claim 11, wherein in the sedimentation washing towers (3)
and (6), there are provided combined internals (16) composed of corrugated
plate (17) with an opening ratio of 10-40% and with pores at its wavecrest
portions and wave valley portions, and wherein said corrugated plate (17)
are horizontally mounted with the wave valley thereof at an angle of
90.degree. to the wave valley of the corrugated plate thereover and/or
thereunder.
Description
FIELD OF THE INVENTION
The present invention relates to a continuous alkylation process and a
liquid-solid circulating fluidized bed system for the continuous
alkylation process. More specifically, the invention relates to a
continuous alkylation process of aromatics or their derivatives in the
presence of a solid acid catalyst and a liquid-solid circulating fluidized
bed system for such a process in which the reaction of the reactants and
the regeneration of the used solid acid catalyst proceed continuously.
BACKGROUND OF THE INVENTION
Alkylation reaction is one of the most important reactions in the
petrochemical industry, for example, the product of the alkylation of
benzene with propylene is the raw material for propanone and phenol; the
alkylation of iso-butane with butene produces high octane number gasoline;
and the alkylation of benzene with long chain olefins (C.sub.10 -C.sub.18
olefins) produces the raw materials for detergents and surfactants. The
previous catalysts for the above processes are liquid catalysts, for
example, H.sub.2 F, H.sub.2 SO.sub.4, H.sub.3 PO.sub.4, AlCl.sub.3,
ZnCl.sub.2, and so on. However, the use of these catalysts brings about a
lot of problem such as the separation of catalyst from products, treatment
of the used catalyst, corrosion to the equipment and the harm to the
health of the operators. Therefore, in recent years, it is an interesting
subject to develop new solid catalysts to replace the above liquid
catalysts for the alkylation processes.
The solid acid catalysts which have been proposed for the alkylation
process are zeolite molecular sieves, such as HX, HY, HZSM-5, USY and
REHY; halogen-containing cation exchanged resins, halogen-containing
superacids, superacids of SO.sub.4.sup.2- /M.sub.x O.sub.y type, and
composite oxide superacids. These solid catalysts are susceptible to
deactivation due to the deposition of coke formed from the polymerization
of the olefins on the catalyst surface , hence, the activity of these
catalysts will decrease quickly, especially, for the catalyst with high
activity. This means that the solid catalysts will be run only with a very
low activity during the process if no special treatment is given to these
used catalysts. Although different techniques, such as the introduction of
the Group VIII elements or the rare earth elements into the catalyst, have
been used to prevent coke deposition on the catalyst and to improve the
service life of the catalysts, the results are not satisfactory.
Another approach to the problem is to develop a new process, in which the
coke deposited catalyst are regenerated timely. To satisfy the requirement
of the process wherein the alkylation reaction in the presence of a solid
catalyst and the regeneration of the used solid catalyst (referred to as
reaction-regeneration cycle hereafter) occur alternatively, it is critical
to develop new process equipment in which the above process can be
realized (Vora, B. V. et al., Tenside Surfactant Detergent, 28(4),
287-294, 1991). It has been reported that the fixed bed and continuously
stirred batch reactors have been used for such a process.
In the fixed bed reactor, when the activity of the catalyst decreases to a
certain level, the reactor will be switched to regeneration phase. The
regeneration proceeds in the same reactor by changing the reactants into
regenerating reagent. After the coke deposited on the catalyst surface is
removed by the regenerating reagent, the reactor will be switched to
reaction phase again. By this way, the reaction-regeneration cycle
advances alternately and the process proceeds continuously. A pilot
process based upon the above philosophy has been developed by UOP (U.S.
Pat. No. 5,012,021). Because there is a time interval between reaction and
regeneration phase, there should be 3 or more reactors for total process.
The situation of the continuously stirred batch reactor is the same as that
of the fixed bed reactor. The fresh solid catalyst contacts the reactants
in the reactor and reaction undergoes in it. When the activity of the
catalyst decreases to a certain level, the reactants and products are
withdrawn out of the reactor, while the catalyst remains within the
reactor. Subsequently, the regenerating reagent is introduced into the
reactor and the catalyst is regenerated. After that, the reactor is
switched to reaction phase again, and this process proceeds repeatedly.
In summary, all the prior art reaction-regeneration cycle undergoing either
in the fixed bed reactor or in the continuously stirred batch reactor, are
in a batch mode, the reaction period depends on the deactivation rate
constants of the catalyst. For the catalyst susceptible to deactivation,
frequent switching brings about the following disadvantages: overelaborate
operation, huge investment cost, unnecessary loss of reactants and
regenerating reagent when the switching is undertaken, the low production
efficiency under batch operation, and the most important, the decreasing
activity or even very low activity of the catalyst throughout the
reaction.
It is, therefore, an object of the present invention to provide a process
for continuous alkylation of aromatics or their derivatives in the
presence of a solid acid catalyst, wherein the reaction-regeneration cycle
takes place continuously.
Another object of the present invention is to provide a liquid-solid
circulating fluidized bed system in which continuous alkylation is carried
out.
SUMMARY OF THE INVENTION
The process for continuous alkylation of aromatics or their derivatives
provided by the present invention is shown in FIG. 1, which comprises
(a) contacting the reactants with a solid acid catalyst in a liquid-solid
concurrent upflow reactor (1);
(b) passing the liquid-solid mixture consisting of used solid acid catalyst
and the unreacted reactants and the products into a vortical liquid-solid
separator (2) to give separated used solid acid catalyst;
(c) passing said separated used solid acid catalyst through a sedimentation
washing tower (3) into a liquid-solid concurrent upflow regenerator (4);
(d) contacting said separated used solid acid catalyst in said regenerator
(4) with the regenerating reagent which is a reactant selected from the
group comprising aromatics and their derivatives;
(e) passing the liquid-solid mixture consisting of the regenerated catalyst
and the regenerating reagent into a vortical liquid-solid separator (5) to
give separated regenerated solid acid catalyst; and
(f) returning the separated regenerated solid acid catalyst to a
sedimentation washing tower (6), then into said reactor (1). Thus, the
reaction-regeneration cycle is carried out continuously.
The structure of the liquid-solid circulating fluidized bed system provided
by the present invention suitable for the continuous alkylation process
according to the present invention is shown in FIG. 1, which comprises a
liquid-solid concurrent upflow reactor (1), a sedimentation washing tower
(3) for the used catalyst, a liquid-solid concurrent upflow regenerator
(4), a sedimentation washing tower (6) for the regenerated catalyst, and
two vortical liquid-solid separator (2) and (5), wherein the top of said
reactor (1), which has two inlets (7) and (8) for reactants, connects with
said vortical liquid-solid separator (2), which in turn connects with the
top of said sedimentation washing tower (3), and the bottom of said
reactor (1) connects with the bottom of sedimentation washing tower (6),
and wherein the top of said regenerator (4), which has two inlets (11) and
(12) for regenerating reagent and is set up parallel to said reactor (1),
connects with said vortical liquid-solid separator (5), which in turn
connects with the top of said sedimentation washing tower (6), and the
bottom of said regenerator (4) connects with the bottom of said
sedimentation washing tower (3).
BRIEF DESCRIPTION OF DRAWINGS
For a more complete description of the continuous alkylation process of
this invention, reference shall be made to the accompanying figures
illustrating the present continuous liquid-solid circulating fluidized bed
system, wherein:
FIG. 1 represents the continuous alkylation process according to the
invention and the schematic apparatus of the continuous liquid-solid
circulating fluidized bed system.
FIG. 2 represents the schematic apparatus of the combined distributors
installed in the reactor and regeneratator.
FIG. 3 represents the structure of internals installed in the sedimentation
washing tower.
FIG. 4 represents the comparison of the activity of the catalyst obtained
in the liquid-solid circulating fluidized bed system and in continuously
stirred batch reactor.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term "liquid-solid concurrent upflow reactor/
regenerator" refers to a column set up vertically, in which the liquid
(e.g. the reactants or regenerating reagent) and the solid (e.g. the solid
acid catalyst) move upwards concurrently, they can be any known column
suitable for such a reaction or regeneration.
As used herein, the term "sedimentation washing tower" refers to a tower in
which the solid acid catalyst, while settling, are washed by the liquid
moving upwards.
As used herein, the term "liquid-solid vortical separator" refers to a
separator, and the mixture consisting of solid acid catalyst and liquid
enters into it in the tangent direction and are separated from each other
in it.
As used herein, the term "opening ratio" refers to the ratio of the pore
area of a plate to the total area of the plate.
As used herein, the term "voidage" refers to the ratio of the volume of the
liquid contained in a column to the total volume of the same column, with
the volume of liquid and solid, if any, contained in a column equal to the
volume of the same column.
The process for continuous alkylation of aromatics or their derivatives
provided by the present invention is shown in FIG. 1. The reactants
provided according to the required ratio of reactants and mixed well are
divided into two parts, one part is pumped by a metering pump into the
reactor 1 via the first inlet 7, and the other is pumped into the reactor
1 via the second inlet 8; the reactants which get into the reactor via the
first inlet 7 are used to bring the solid acid catalyst particles to a
circulating fluidized state, while the reactants which go into the reactor
via the second inlet 8 are use to change the resistance to catalyst
particles at the inlet, hence to regulate the catalyst circulation rate.
After passing through the combined distributor 9, the reactants enter into
the concurrent upflow reactor 1. In reactor 1, the reactants get into
contact with the solid acid catalyst of a diameter of 0.05-0.8 mm, and the
alkylation reaction takes place. The flow rates of reactants and catalyst
are maintained in such a way as to keep a voidage of the reactor of
0.68-0.95. Under the operating conditions of a temperature of
0.degree.-350.degree. C. and a pressure of 1-30 atm, the catalyst is
transported by the reactants and products from the bottom to the top of
the reactor, with the liquid flow rate being 1-15 times the terminal
settling velocity of the catalyst particles, at last the liquid and solid
mixture leaves the reactor and enters into the vortical liquid-solid
separator 2 in the tangent direction at a liquid flow rate of 1-10 m/s.
The separated liquid products (which contains very little unconverted
reactants) get into the product reservoir from the product outlet 10,
while the used catalyst particles enters into the sedimentation washing
tower 3. In the sedimentation washing tower 3, the used catalyst particles
gets into contact with the washing reagent which is the same as the
reactant(s) selected from the group comprising aromatics and their
derivatives, and the washing reagent moves upwards in the tower at a flow
rate 0.5-5 times the terminal settling velocity of the catalyst particles
and takes away the product and some coke deposits formed on the catalyst
surface, then, the used catalyst particles enter into the concurrent
upflow regenerator 4, the regenerating reagent which is a reactant
selected from the group comprising aromatics and their derivatives is
divided into two parts, one part is pumped by a metering pump into the
regenerator 4 via the first inlet 11, and the other is pumped into the
regenerator 4 via the second inlet 12; the regenerating reagent which gets
into the regenerator 4 via the first inlet 11 is used to bring the used
catalyst particles to a circulating fluidized state, while the
regenerating reagent which goes into the regenerator 4 via the second
inlet 12 is used to change the resistance to used catalyst particles at
the inlet, hence to regulate the circulation rate of the used catalyst.
After passing through the combined distributor 9, the regenerating reagent
enters into the concurrent upflow regenerator 4. In the regenerator 4, the
regenerating reagent contacts the used solid acid catalyst and removes the
coke deposited on it. The flow rates of regenerating reagent and the used
catalyst are maintained in such a way as to keep a voidage of the
regenerator 4 of 0.68-0.95. Under the operating conditions of a
temperature of 70.degree.-450.degree. C. and a pressure of 1-25 atm, the
used catalyst is transported by the regenerating reagent from the bottom
to the top of the regenerator 4, with the liquid flow rate being 1-15
times the terminal velocity of the used catalyst particles, at last the
liquid and solid mixture leaves the reactor and enters into the vortical
liquid-solid separator 5 in the tangent direction at a liquid flow rate of
1-10 m/s. The separated regenerating reagent goes into the regenerating
reagent reservoir from the regenerating reagent outlet 13, while the
regenerated catalyst particles enters into sedimentation washing tower 6.
In the sedimentation washing tower 6, the regenerated catalyst contacts
the washing reagent which is the same as the reactant(s) selected from the
group comprising aromatics and their derivatives, while the washing
reagent moves upwards in the tower at a velocity 0.5-5 times the terminal
settling velocity of the regenerated catalyst particles and further takes
away the coke deposits and remaining washing reagent on it, at last, the
regenerated catalyst particles enter into the concurrent upflow reactor 1,
thus a reaction-regeneration cycle is finished. By repeating such a
reaction-regeneration cycle a continuous alkylation process with a high
catalyst activity is attained.
The continuous alkylation process provided by the present invention
realizes the alkylation reaction in the presence of a solid acid catalyst
in a continuous manner and due to the fact that the reaction-regeneration
cycle is operated under circulating fluidization, the catalyst can be
ensured to be of high activity. Such a alkylation can be, for example, the
alkylation of aromatics or their derivatives with olefins with 2-20 carbon
atoms in the presence of various types of solid acid catalyst. In the
process of the present invention, the reactants and regenerating reagent
get into the system by two paths, moreover, the flow rates of the two
parts can be regulated respectively, hence, both the reaction conversion
and the regenerating efficiency can be controlled. In the present process,
because the regenerating reagent and the washing reagent are the same
aromatic or its derivatives as the reactants, the process is simplified by
eliminating a subsequent separation step and by eliminating pollution of
the reactants by the regenerating reagent other than the reactants.
The present invention can also be used in other similar heterogeneous
catalytic reaction systems provided that the reactants or the products can
be used to remove the coke or other pollutants deposited on the catalyst,
for example, the alkylation of iso-paraffine with butene to give the high
octane number gasoline can be carried out under 10-30 atm and
0.degree.-100.degree. C. with TMP (trimethyl pentane) used as the
regenerating reagent.
The liquid-solid circulating fluidized bed system suitable for the
continuous alkylation process according to the invention is shown in FIG.
1, which mainly comprises six parts: a liquid-solid concurrent upflow
reactor 1, a sedimentation washing tower 3 for the used catalyst, a
liquid-solid concurrent upflow regenerator 4, a sedimentation washing
tower 6 for the regenerated catalyst, and two vortical liquid-solid
separators 2 and 5. The six parts are set up vertically with said
liquid-solid concurrent upflow reactor 1 parallel to said liquid-solid
concurrent upflow regenerator 4, said sedimentation washing tower 3
parallel to said sedimentation washing tower 6, and said vortical
liquid-solid separator 2 parallel to said vortical liquid-solid separator
5. The top of said liquid-solid concurrent upflow reactor 1 connects with
said vortical liquid-solid separator 2, which in turn connects with the
top of said sedimentation washing tower 3, while the bottom of said
liquid-solid concurrent upflow reactor 1 connects with the bottom of said
sedimentation washing tower 6, and the top of said liquid-solid concurrent
upflow regenerator 4 connects with said vortical liquid-solid separator 5,
which in turn connects with the top of said sedimentation washing tower 6,
while the top of said liquid-solid concurrent upflow regenerator 4
connects with the bottom of said sedimentation washing tower 3. The
liquid-solid concurrent upflow reactor 1 or regenerator 4 has two inlets 7
and 8 for reactants or 11 and 12 for regenerating reagent, and has a
combined distributor 9 to connect the two inlets, which is composed of the
multi-tube distributor 14 and the porous plate distributor 15, as shown in
FIG. 2. The multi-tube distributor has an opening ratio of 2-15% and the
porous distributor has an opening ratio of 0.5-5%. The raw materials get
into the reactor or the regenerator via the two inlets and pass through
the tubes or the outside of the tubes of the combined distributor. In the
sedimentation washing tower 3 and 6, there are the combined internals 16
to increase the interaction between the liquid and solid phases. The
internals is made up of the corrugated plate 17, which is shown in FIG. 3.
Besides the corrugated plate, other baffler such as the plate baffler or
the pagoda type baffler, can also be used. There are pores at the
wavecrest portions and the wave valley portions of the corrugated plate,
which is provided for the liquid and solid to pass through, with the
diameter of the pore being 1/20-1/50 of the diameter of the washing tower,
and the opening ratio being 10-40%. The corrugated plates are horizontally
mounted with wave valley thereof at an angle of 90.degree. to the wave
valley of the corrugated plate thereover and/or thereunder. At the bottom
of the sedimentation washing tower 3 or 6,. there is a liquid inlet 18 for
the regenerating reagent or the washing reagent. There is a valve 19 on
the joint position between the bottoms of sedimentation washing tower and
the reactor or the regenerator.
The liquid-solid circulating fluidized bed system provided by the present
invention can realize the continuous alkylation process in the presence of
a solid acid catalyst and can ensure the operation with a high activity of
the catalyst. Because the liquid and solid phases are in a plug flow, the
reaction or regeneration gives high conversion or efficiency and the
temperature of the systems is distributed uniformly in axial direction and
easy to control. There are two inlets at the bottoms of the reactor and
regenerator, so the conversion in the reactor and the regenerating
efficiency in the regenerator can be controlled by regulating the flow
rates via the inlets. The vortical liquid-solid separator is chosen for
the present system because the centrifugal force provided by the structure
of such a separator enables the liquid and solid mixture entering in the
tangent direction to be separated from each other at a high speed in high
efficiency. Because the combined internals, especially the corrugated
plate, is installed in the sedimentation washing tower, the contact
between the washing reagent and the solid catalyst is highly efficient and
the washing is highly effective, thus the catalyst with a clean active
surface is provided for the reactor.
PREFERRED EMBODIMENT OF THE INVENTION
The following examples are provided to illustrate the invention and its
advantages more clearly, but the present invention is not restricted to
these examples.
EXAMPLE 1
Example 1 illustrates that the process of the present invention can keep
high conversion of the reactants under long time continuous operation.
The dodecene and benzene undergo alkylation in the presence of a supported
HY zeolite catalyst by the process shown in FIG. 1. The inner diameter of
the reactor and the regenerator are the same, and the ratio of height to
diameter is 10:1, with the reaction temperature being 110-120.degree. C.,
the regeneration temperature being 165-175.degree. C., the pressure within
the reactor or the regenerator being 4.5-6.0 atm, and the flow rates of
the reactants or the regenerating reagent being 10 liter/hour
respectively, the conversion of dodecene at the outlet of the reactor are
kept at 99.5% throughout the 200 hours continuous operation.
Table 1 shows the product distributions of the linear alkylbenzene of the
alkylation with HF catalyst and HY catalyst by the present process. The
results in Table 1 indicate that the product by the present process has a
higher yield of 2-phenyldodecane and 3- phenyldodecane than by HF catalyst
process. The high content of 2- phenyldodecane in the product will
increase the biodegradability of the final detergent and the high content
of 3-phenyldodecane in the product will increase the detersive efficiency
of the final detergent, which means that the product distribution by the
present process has distinguished characteristics.
TABLE 1
______________________________________
Comparison of the product distribution by different processes
2-P 3-P 4-P 5-P 6-P
______________________________________
HF Process 20 17 16 23 24
Present 50 24 13 8 5
Invention
______________________________________
EXAMPLE 2
This example illustrates that the liquid-solid circulating fluidized bed
system of the present invention makes the catalyst display higher activity
than the continuously stirred batch reactor does.
The dodecene and benzene undergo alkylation in the presence of a supported
HY zeolite catalyst in the liquid-solid circulating fluidized bed system
and the continuously stirred batch reactor respectively under a pressure
of 3 atm, the results are shown in FIG. 4, where the solid line represents
the activity of catalyst in the continuously stirred batch reactor, while
the dotted line represents the activity of catalyst in the liquid-solid
circulating fluidized bed system, the curves (1), (2) and (3) corresponds
to the reaction temperatures of 70.degree. C., 80.degree. C. and
90.degree. C. respectively.
It can be seen that although the activity of the catalyst in the
continuously stirred batch reactor is some higher at the beginning of the
reaction, the activity of catalyst decreases very quickly; on the other
hand, the initial activity coefficient of catalyst in the circulating
fluidized bed system is about 0.8 while the activity is kept at this value
for long time operation.
Top